Overview of the patients and leads
We conducted an entirely concentrated search on the documents of all
patients who had undergone epicardial lead implantation in the Shaheed
Rajaie Cardiovascular, Medical & Research Center during 2015-2018. All
documentations were retrospectively reviewed. According to a systematic
search on previous studies on epicardial leads,1,2 the
following data were selected and extracted from the documentation
regarding each patient; age, sex, past medical history of congenital
heart disease (CHD) with exact type. The following epicardial lead
characteristics were also reviewed and extracted, including indication
for pacemaker implantation, symptoms before implantation, lead type
(unipolar non-steroid-eluting and bipolar steroid-eluting), brand
(Medtronic and St. Jude), device type (CRT, PPM-DR, and PPM-SR), pace
location (atrial, and left ventricular, and right ventricular), pacing
mode (DDD, DDDR, VDD, VVI, VVIR). For the 11 patients who had more than
one-time epicardial lead implantation (10 patients with two and one had
three), their second and third lead was also enrolled as a new lead, and
its characteristics were recorded. As a result, for 77 patients in the
study, 89 leads were enrolled. Furthermore, the electrocardiogram (ECG),
and echocardiogram (echo) of the patients after each lead implantation
were obtained, and their data was reviewed, and extracted by an expert.
ECG data consisted of V1 R/S greater than 1 (yeas or no), QRS Duration
(millisecond or ms.), and notch position. Echocardiographic data
included left ventricular end diastolic diameter (LVEDd), left
ventricular end systolic diameter (LVESd), and left ventricular ejection
fraction (LVEF).